Earth-sized planet orbiting nearest star

PARIS, France - Agence France-Presse

The planet swings close to the star Alpha Centauri B, one of a triple star system that is 4.3 light years away, which is just next door to us.

European astronomers yesterday reported they had detected a planet with about the mass of Earth which orbits the closest star to the Sun. The observation breaks new ground in the hunt for exoplanets, worlds that exist in other solar systems, although the planet itself is not “another Earth” as it is located in a scorchingly hot zone.

The planet swings close to the star Alpha Centauri B, one of a triple star system that is 4.3 light years away, which in cosmic terms is just next door to us.

The find was made thanks to a telltale wobble in the star’s motion, tugged by the gravitational pull of the passing planet.

The signal is “tiny but real,” said Xavier Dumusque of the Geneva Observatory in Switzerland. “It’s an extraordinary discovery and it has pushed our technique to the limit.” The transiting planet makes the star move back and forth, in relation to Earth, by less than two kilometers per hour, about the speed of a baby crawling.

The minute motion was detected using an instrument called HARPS, installed on the European Southern Observatory (ESO) at La Silla, in the depths of the Atacama desert in Chile. It took hundreds of observations, spanning more than four years, for the “wobble” to be teased out of the other light signals.

‘Life can exist beyond our world’
The study shows the technical advances in exoplanet research since the very first was spotted in 1995. Since then more than 750 exoplanets have been confirmed as sightings and another 2,300 claims are pending.None, however, is both Earth-sized and in a habitable area, something that would bolster theories that life can exist beyond our world.

The quest is for a rocky planet the size of Earth in the “Goldilocks zone.”